1. Field
This invention relates to rotary sprinklers and, more particularly, to such sprinklers having a plurality of selectively adjustable nozzle units.
2. Description of the Prior Art
Rotary sprinklers having a plurality of jet driven arms for distributing water on a lawn or garden have been well known in the yard for a number of years. U.S. Pat. No. 4,905,903, entitled "Sprinkler", discloses a contemporary rotary sprinkler having three arms, or "nozzle supports," with each such arm having a rotatable nozzle head disposed on the distal end thereof. Each nozzle head is selectively rotatable between three independent positions, with a different number of nozzles placed in use in each position. Each nozzle head is also rotatable to a position wherein none of the respective nozzles are in use (i.e., none of the nozzles are in fluid communication with the water supply). The angular orientation of each nozzle head may also be independently adjusted, thereby controlling the rotational velocity of the arm assembly.
Other conventional rotary sprinklers provide two or three arms radially projecting from a central hub, which is rotatably secured to a base, with each arm having a fixed jet operatively disposed thereon. Such sprinklers are typically very inexpensive to manufacture, but do not provide the degree of adjustability required for some applications. Specifically, some conventional sprinklers do not provide means for adjusting the water flow and/or the directional orientation of the nozzles.
Conceptually, the sprinkler disclosed in the '903 patent provides a high degree of adjustability for the spray pattern of the water distributed thereby. Each of the three arms includes a nozzle head with three separate sets of nozzle units, and each of the three nozzle units per arm has a different number of nozzles formed therein. The angular orientation of each nozzle unit may be varied considerably, including a position wherein no nozzles are in operation, so that the rotational velocity of the '903 sprinkler is, at least theoretically, almost infinitely adjustable.
In practice, however, the sprinkler disclosed in the '903 patent has been found to be unnecessarily complicated for its intended purpose. In the vast majority of applications, there is little or no discernible difference between most of the various patterns of water distribution provided by the '903 sprinkler. Similarly, it has been found that there is little or no practical distinction in the effectiveness of the sprinkler when the nozzle units are set at many of the available angular orientations. The conceptual range of rotational velocities available with the '903 sprinkler is unrealistic given the practical limitations in water pressure and bearing efficiency. In short, the unusually complicated operation of the sprinkler disclosed in the '903 patent is not justified by the relatively few advantages provided by its high degree of adjustability.
There is a need in the industry for a rotary sprinkler of simplified design and operation, which provides a suitable variety of water distribution patterns and rotational velocities.